Fermi surface of the filled-skutterudite superconductor LaRu4P12: A clue to the origin of the metal-insulator transition in PrRu4P12

TL;DR

This study investigates the Fermi surface of LaRu4P12 using dHvA effect and magnetoresistance, revealing insights into the electronic structure and its relation to the metal-insulator transition in PrRu4P12.

Contribution

It provides detailed Fermi surface data for LaRu4P12 and clarifies the role of c-f hybridization and Fermi surface nesting in the M-I transition of PrRu4P12.

Findings

Fermi surface branches match band-structure calculations

Large effective mass enhancement observed in LaRu4P12

FS nesting and c-f hybridization are key to the M-I transition

Abstract

We report the de Haas-van Alphen (dHvA) effect and magnetoresistance in the filled-skutterudite superconductor LaRu4P12, which is a reference material of PrRu4P12 that exhibits a metal-insulator (M-I) transition at T_MI~60 K. The observed dHvA branches for the main Fermi surface (FS) are well explained by the band-structure calculation, using the full potential linearized augmented-plane-wave method with the local-density approximation, suggesting a nesting instability with q =(1,0,0) in the main multiply connected FS as expected also in PrRu4P12. Observed cyclotron effective masses of (2.6-11.8)m_0, which are roughly twice the calculated masses, indicate the large mass enhancement even in the La-skutterudites. Comparing the FS between LaRu4P12 and PrRu4P12, an essential role of c-f hybridization cooperating with the FS nesting in driving the the M-I transition in PrRu4P12 has been clarified.